Question

Very often an organism’s traits are caused by a combination of its genes and its environment. Think about the green color you supposedly saw in the genetically transformed bacteria under UV light:

_{18) What two factors must be present in the bacteria’s environment for you to see the green color? (Hint: one factor is in the plate and the other factor is in how you look at the bacteria).}

_{19) What do you think each of the two environmental factors you listed above are doing to cause the genetically transformed bacteria to turn green?}

Answer 1

18. Factors:

A. Presence of chromophore within GFP (made up of amino acids serine, tyrosine, glycine)

B. Presence of UV light in the environment

19. Only the presence of GFP gene does not confer fluorescence to the cells. The particular amino acids must come together, undergo a particular chemical reaction and form the chromophore which is essential for fluorescence. This chromophore absorbs blue or UV radiation from its environment, and thereby shows green colored fluorescence. Without absorbing the UV light, there will be no observable green fluorescence.